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ACS Applied Materials & Interfaces Oct 2023Although conductive hydrogels (CHs) have been investigated as the wearable sensor in recent years, how to prepare the multifunctional CHs with long-term usability is...
Although conductive hydrogels (CHs) have been investigated as the wearable sensor in recent years, how to prepare the multifunctional CHs with long-term usability is still a big challenge. In this paper, we successfully prepared a kind of conductive and self-adhesive hydrogel with a simple method, and its excellent ductility makes it possible as a flexible strain sensor for intelligent monitoring. The CHs are constructed by poly(vinyl alcohol) (PVA), polydopamine (PDA), and phytic acid (PA) through the freeze-thaw cycle method. The introduction of PA enhanced the intermolecular force with PVA and provided much H for augmented conductivity, while the catechol group on PDA endows the hydrogel with self-adhesion ability. The PVA/PA/PDA hydrogel can directly contact with the skin and adhere to it stably, which makes the hydrogel potentially a wearable strain sensor. The PVA/PA/PDA hydrogel can monitor human motion signals (including fingers, elbows, knees, etc.) in real-time and can accurately monitor tiny electrical signals for smile and handwriting recognition. Notably, the composite CHs can be used in a normal environment even after 4 months. Because of its excellent ductility, self-adhesiveness, and conductivity, the PVA/PA/PDA hydrogel provides a new idea for wearable bioelectronic sensors.
Topics: Humans; Adhesives; Hydrogels; Resin Cements; Electric Conductivity; Adhesiveness; Phytic Acid
PubMed: 37802535
DOI: 10.1021/acsami.3c12831 -
ACS Nano Dec 2021Dry adhesives that combine strong adhesion, high transparency, and reusability are needed to support developments in emerging fields such as medical electrodes and the...
Dry adhesives that combine strong adhesion, high transparency, and reusability are needed to support developments in emerging fields such as medical electrodes and the bonding of electronic optical devices. However, achieving all of these features in a single material remains challenging. Herein, we propose a pressure-responsive polyurethane (PU) adhesive inspired by the octopus sucker. This adhesive not only showcases reversible adhesion to both solid materials and biological tissues but also exhibits robust stability and high transparency (>90%). As the adhesive strength of the PU adhesive corresponds to the application force, adhesion could be adjusted by the preloading force and/or pressure. The adhesive exhibits high static adhesion (∼120 kPa) and 180° peeling force (∼500 N/m), which is far stronger than those of most existing artificial dry adhesives. Moreover, the adhesion strength is effectively maintained even after 100 bonding-peeling cycles. Because the adhesive tape relies on the combination of negative pressure and intermolecular forces, it overcomes the underlying problems caused by glue residue like that left by traditional glue tapes after removal. In addition, the PU adhesive also shows wet-cleaning performance; the contaminated tape can recover 90-95% of the lost adhesion strength after being cleaned with water. The results show that an adhesive with a microstructure designed to increase the contribution of negative pressure can combine high reversible adhesion and long fatigue life.
Topics: Adhesiveness; Adhesives; Biomimetic Materials; Biomimetics; Water
PubMed: 34797635
DOI: 10.1021/acsnano.1c03882 -
Journal of Materials Chemistry. B Feb 2022Adhesives have attracted extensive attention in biomedical applications in recent years. However, the development of adhesives with strong adhesion in both dry and...
Adhesives have attracted extensive attention in biomedical applications in recent years. However, the development of adhesives with strong adhesion in both dry and underwater conditions and antibacterial properties is still a challenge. Herein, a biomimetic adhesive (DP@TA/Gel) was developed based on the adhesion mechanism of mussel in water, from adhesion and solidification to avoiding excessive oxidization processes. DP@TA/Gel exhibited rapid strong nonspecific adhesiveness to diverse materials including wood (485 kPa) metal (507 kPa), plastic (74 kPa), and even fresh biological tissue (39 kPa) in dry conditions. Specially, owing to its biomimetic design, DP@TA/Gel could imitate the mussel adhesion mechanism underwater, endowing it with robust (38 kPa), highly repeatable (at least 15 times) and long-term (at least 120 h) stable adhesion even in underwater conditions. Remarkably, DP@TA/Gel also exhibited high adhesiveness in various water environments, including seawater, and a wide range of pH (3-11) and NaCl concentration (0.9-10%) solutions without any stimulus. In addition, DP@TA/Gel showed excellent biocompatibility and antibacterial properties. Thus, the DP@TA/Gel adhesive has appealing potential biomedical applications such as sutureless wound closure and as a tissue adhesive.
Topics: Adhesiveness; Adhesives; Animals; Anti-Bacterial Agents; Biomimetics; Bivalvia; Water
PubMed: 35076052
DOI: 10.1039/d1tb02215f -
Carbohydrate Polymers Feb 2021For conductive hydrogels applied in biosensors, wearable devices and so forth, multifunctionality is an inevitable trend of development to meet various practical...
For conductive hydrogels applied in biosensors, wearable devices and so forth, multifunctionality is an inevitable trend of development to meet various practical requirements and enhance human experience. Herein, inspired by nanocomposite, double-network (DN) and mussel chemistry, a new Graphene oxide@Dopamine/Alginate/Poly(acrylic acid-co-acrylamide) [GO@DA/Alginate/P(AAc-co-AAm)] hydrogel was fabricated through one-pot in-situ radical copolymerization. GO@DA nanofillers, prepared via GO confined DA polymerization, imparted the hydrogel with remarkable adhesiveness. Alginate/P(AAc-co-AAm) DN matrix, physically and chemically crosslinked by Fe and N,N'-Methylenebisacrylamide, made hydrogels ultrastretchable, self-healing and biocompatible. With contents of DA and alginate accurately regulated, the tensile strength, elongation, adhesion strength and conductivity of the optimal hydrogel could reach 320.2 kPa, 1198 %, 36.9 kPa and 3.24 ± 0.12 S/m, respectively. What's more notable was that the synergistic integration of repeatable adhesiveness, strain sensitivity, use stability, self-healing ability and biocompatibility provided such hydrogels with tremendous possibility of practical application for strain sensors.
Topics: Acrylamides; Adhesiveness; Adhesives; Alginates; Animals; Biocompatible Materials; Biosensing Techniques; Bivalvia; Cell Survival; Dopamine; Electric Conductivity; Graphite; Humans; Hydrogels; Mice; NIH 3T3 Cells; Nanogels; Patch Tests; Polymerization; Tensile Strength
PubMed: 33357879
DOI: 10.1016/j.carbpol.2020.117316 -
Colloids and Surfaces. B, Biointerfaces Mar 2023Adhesive and tough hydrogels have received increased attention for their potential biomedical applications. However, traditional hydrogels have limited utility in tissue...
Adhesive and tough hydrogels have received increased attention for their potential biomedical applications. However, traditional hydrogels have limited utility in tissue engineering because they tend to exhibit low biocompatibility, low adhesiveness, and poor mechanical properties. Herein, the use of the eggshell membrane (ESM) for developing tough, cell-friendly, and ultra-adhesive hydrogels is described. The ESM enhances the performance of the hydrogel network in three ways. First, its covalent cross-linking with the polyacrylamide and alginate chains strengthens the hydrogel network. Second, it provides functional groups, such as amine and carboxyl moieties, which are well known for enhancing the surface adhesion of biomaterials, thereby increasing the adhesiveness of the hydrogel. Third, it is a bioactive agent and improves cell adhesion and proliferation on the constructed scaffold. In conclusion, this study proposes the unique design of ESM-incorporated hydrogels with high toughness, cell-friendly, and ultra-adhesive properties for various biomedical engineering applications.
Topics: Animals; Hydrogels; Adhesives; Egg Shell; Biocompatible Materials; Adhesiveness
PubMed: 36682295
DOI: 10.1016/j.colsurfb.2023.113156 -
Nature Nov 2019Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals...
Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals interactions. However, such instant adhesion is challenging when wet surfaces such as body tissues are involved, because water separates the molecules of the two surfaces, preventing interactions. Although tissue adhesives have potential advantages over suturing or stapling, existing liquid or hydrogel tissue adhesives suffer from several limitations: weak bonding, low biological compatibility, poor mechanical match with tissues, and slow adhesion formation. Here we propose an alternative tissue adhesive in the form of a dry double-sided tape (DST) made from a combination of a biopolymer (gelatin or chitosan) and crosslinked poly(acrylic acid) grafted with N-hydrosuccinimide ester. The adhesion mechanism of this DST relies on the removal of interfacial water from the tissue surface, resulting in fast temporary crosslinking to the surface. Subsequent covalent crosslinking with amine groups on the tissue surface further improves the adhesion stability and strength of the DST. In vitro mouse, in vivo rat and ex vivo porcine models show that the DST can achieve strong adhesion between diverse wet dynamic tissues and engineering solids within five seconds. The DST may be useful as a tissue adhesive and sealant, and in adhering wearable and implantable devices to wet tissues.
Topics: Acrylic Resins; Adhesiveness; Adhesives; Animals; Chitosan; Cross-Linking Reagents; Desiccation; Gelatin; Heart; Hydrogels; Hydrogen Bonding; Lung; Mice; Prostheses and Implants; Rats; Static Electricity; Stomach; Swine; Time Factors; Water; Wearable Electronic Devices; Wettability
PubMed: 31666696
DOI: 10.1038/s41586-019-1710-5 -
Journal of the Royal Society, Interface Jan 2019Surface microstructures in nature enable diverse and intriguing properties, from the iridescence of butterfly wings to the hydrophobicity of lotus leaves to the...
Surface microstructures in nature enable diverse and intriguing properties, from the iridescence of butterfly wings to the hydrophobicity of lotus leaves to the controllable adhesion of gecko toes. Many artificial analogues exist; however, there is a key characteristic of the natural materials that is largely absent from the synthetic versions-spatial variation. Here we show that exploiting spatial variation in the design of one class of synthetic microstructure, gecko-inspired adhesives, enables one-way friction, an intriguing property of natural gecko adhesive. When loaded along a surface in the preferred direction, our adhesive material supports forces 100 times larger than when loaded in the reverse direction, representing an asymmetry significantly larger than demonstrated in spatially uniform adhesives. Our study suggests that spatial variation has the potential to advance artificial microstructures, helping to close the gap between synthetic and natural materials.
Topics: Adhesiveness; Adhesives; Animals; Biomimetic Materials; Friction; Lizards
PubMed: 30958166
DOI: 10.1098/rsif.2018.0705 -
Acta Odontologica Scandinavica Nov 2014To examine the initial viscosity and adhesive strength of modern denture adhesives in vitro.
OBJECTIVE
To examine the initial viscosity and adhesive strength of modern denture adhesives in vitro.
MATERIALS AND METHODS
Three cream-type denture adhesives (Poligrip S, Corect Cream, Liodent Cream; PGS, CRC, LDC) and three powder-type denture adhesives (Poligrip Powder, New Faston, Zanfton; PGP, FSN, ZFN) were used in this study. The initial viscosity was measured using a controlled-stress rheometer. The adhesive strength was measured according to ISO-10873 recommended procedures. All data were analyzed independently by one-way analysis of variance combined with a Student-Newman-Keuls multiple comparison test at a 5% level of significance.
RESULTS
The initial viscosity of all the cream-type denture adhesives was lower than the powder-type adhesives. Before immersion in water, all the powder-type adhesives exhibited higher adhesive strength than the cream-type adhesives. However, the adhesive strength of cream-type denture adhesives increased significantly and exceeded the powder-type denture adhesives after immersion in water. For powder-type adhesives, the adhesive strength significantly decreased after immersion in water for 60 min, while the adhesive strength of the cream-type adhesives significantly decreased after immersion in water for 180 min.
CONCLUSION
Cream-type denture adhesives have lower initial viscosity and higher adhesive strength than powder type adhesives, which may offer better manipulation properties and greater efficacy during application.
Topics: Adhesiveness; Adhesives; Denture Retention; Humans; Immersion; Materials Testing; Ointments; Powders; Rheology; Stress, Mechanical; Surface Properties; Temperature; Viscosity; Water
PubMed: 24791610
DOI: 10.3109/00016357.2014.913309 -
Advanced Healthcare Materials Aug 2022Although tissue adhesives have potential advantages over traditional sutures, existing ones suffer from several limitations: slow adhesion kinetic, low mechanical...
Although tissue adhesives have potential advantages over traditional sutures, existing ones suffer from several limitations: slow adhesion kinetic, low mechanical strength, and poor interfacial bonding with wet biological tissues. Herein, a cooperative mussel/slug double-bioinspired hydrogel adhesive (DBHA) composed of a robust adhesive interface and a stretchable dissipative matrix is developed. The DBHA is formed by a cationic polysaccharide (chitosan), an anionic polysaccharide (carboxymethyl cellulose), and a barbell-like dendritic lysine grafted with catechol groups (G3KPCA). Compared to various commercial bio-glues and traditional adhesives, the DBHA has significantly stronger tissue adhesion and enhanced toughness both ex vivo and in vivo. Meanwhile, the DBHA exhibits fast, strong, tough, and durable adhesion to diverse ex vivo tissue surfaces with blood. The adhesion energy between the adhesive and porcine skin can reach 200-900 J m . Additionally, in vivo studies prove that DBHA has good hemostasis of rabbit artery trauma and achieves better wound healing of tissue incision than commercial bio-glues. This study provides a novel strategy for fabricating fast and strong wet adhesives, which can be used in many applications, such as soft robots, tissue adhesives and hemostats.
Topics: Adhesives; Animals; Dendrimers; Hydrogels; Peptides; Rabbits; Swine; Tissue Adhesions; Tissue Adhesives
PubMed: 35657075
DOI: 10.1002/adhm.202200874 -
PloS One 2022In the field of cell and tissue engineering, there is an increasing demand for techniques to spatially control the adhesion of cells to substrates of desired sizes and...
In the field of cell and tissue engineering, there is an increasing demand for techniques to spatially control the adhesion of cells to substrates of desired sizes and shapes. Here, we describe two novel methods for fabricating a substrate for adhesion of cells to a defined area. In the first method, the surface of the coverslip or plastic dish was coated with Lipidure, a non-adhesive coating material, and air plasma was applied through a mask with holes, to confer adhesiveness to the surface. In the second method, after the surface of the coverslip was coated with gold by sputtering and then with Lipidure; the Lipidure coat was locally removed using a novel scanning laser ablation method. These methods efficiently confined cells within the adhesive area and enabled us to follow individual cells for a longer duration, compared to the currently available commercial substrates. By following single cells within the confined area, we were able to observe several new aspects of cell behavior in terms of cell division, cell-cell collisions, and cell collision with the boundary between adhesive and non-adhesive areas.
Topics: Adhesiveness; Adhesives; Cell Adhesion; Cell Engineering; Dictyostelium; Lipids; Methacrylates; Phosphorylcholine; Plastics; Surface Properties; Tissue Engineering
PubMed: 35030217
DOI: 10.1371/journal.pone.0262632